Asplenium trichomanes
Asplenium ruta-muraria
doradille chevelue, maidenhair spleenwort
doradille des murailles, wall rue, wall-rue spleenwort
not proliferous.
not proliferous.
short-creeping, often branched;
scales black throughout or with brown borders, lanceolate, 2–5 × 0.2–0.5 mm, margins entire to denticulate.
short-creeping to erect, often branched;
scales very dark brown throughout, narrowly deltate, 1–3 × 0.1–0.25 mm, margins with widely spaced teeth.
monomorphic.
monomorphic.
reddish brown or blackish brown throughout, lustrous, 1–4(–7) cm, 1/6–1/4 length of blade;
indument absent or of black, linear-lanceolate or filiform scales at base.
reddish brown proximally, green distally, dull, 1–9 cm, (1/2–)1–2 times length of blade;
indument of dark brown, narrowly deltate scales proximally grading into multicellular hairs.
linear, 1-pinnate, 3–22 × 0.5–1.5 cm, thin, glabrous or sparsely pubescent;
base gradually tapered;
apex narrowly acute, not rooting.
deltate-ovate to obovate or oblanceolate, 1–2(–3)-pinnate to 2-pinnate-pinnatifid, 2–6 × 1–4 cm, somewhat thick, glabrous;
base obtuse;
apex acute to rounded, not rooting.
in 15–35 pairs, oblong to oval;
medial pinnae 2.5–8 × 2.5–4 mm;
base broadly cuneate, with or without low, rounded acroscopic auricle;
margins shallowly crenate to serrate or ± entire;
apex obtuse.
in 2–4 pairs, deltate-ovate to obdeltate;
proximal (largest) pinnae 7–30 × 5–20 mm;
base truncate to acute;
margins finely (sometimes coarsely) incised;
apex rounded to acute.
free, evident.
free, evident.
2–4 pairs per pinna, on both basiscopic and acroscopic sides.
as many as 30 or more per pinna, usually 1–5 per segment, on both basiscopic and acroscopic sides.
64 per sporangium.
64 per sporangium.
reddish brown throughout, lustrous, glabrous or nearly so.
green, dull, glabrous except for very sparse, minute hairs.
= 72, 144.
= 144.
Asplenium trichomanes
Asplenium ruta-muraria
In North America, as in Europe, Asplenium trichomanes consists of diploid and tetraploid cytotypes, treated here as subspecies. Asplenium trichomanes subsp. trichomanes, the diploid, is found on noncalcareous rocks. In the southwestern United States it occurs at high elevations. Asplenium trichomanes subsp. quadrivalens, the tetraploid, grows on calcareous substrates and has a more northern distribution (R. C. Moran 1982). Triploid hybrids are known between the diploids and tetraploids (R. C. Moran 1982; W. H. Wagner Jr. and F. S. Wagner 1966).
Subspecies 4 (2 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
The relationship of North American Asplenium ruta-muraria to its European counterparts is incompletely understood and bears further investigation. Based on features of the stems, M. L. Fernald (1928) segregated the North American taxon as A. cryptolepis, but most current authors agree that morphologic differentiation of North American and European material is too slight and inconsistent for recognition at the specific level. In Europe, two ploidy levels are treated as subspecies, diploid A. ruta-muraria subsp. dolomiticum Lovis & Reichstein and tetraploid A. ruta-muraria subsp. ruta-muraria, the latter representing the most compelling case for true autopolyploidy (i.e., based on chromosomal homology) known in ferns (G. Vida 1970). Chromosome counts of North American plants are consistently tetraploid; whether or not these plants are referable to subsp. ruta-muraria will remain unclear until additional evidence (e.g., isozymes) is obtained. Meanwhile, North American material should be designated simply as A. ruta-muraria, the convention used in most current manuals.
Although M. L. Fernald (1928) recognized Asplenium cryptolepis var. ohionis (= A. ruta-muraria var. subtenuifolium Christ), based on its acute rather than rounded segment apices, leaves assignable to this variety may occur on plants also bearing leaves more similar to those of the type variety (R. Cranfill 1980). The former is not recognized taxonomically here.
Numerous hybrids of Asplenium ruta-muraria with various taxa are known from Europe (T. Reichstein 1981), but only three are known from North America, all exceedingly rare. These are the hybrids with A. rhizophyllum (A. × inexpectatum), with A. trichomanes (A. × clermontae Syme), and with A. platyneuron (A. × morganii).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Spores 27-32 µm; on acidic substrates. | subsp. trichomanes |
1. Spores 37-43 µm; on limestone. | subsp. quadrivalens |
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